The present invention relates to a stator coil including sequentially connected segment conductors preferably applicable to an electric rotary machine.
From the view point of providing compact automotive electric rotary machines and increasing the output of these machines, a stator coil including sequentially connected segment conductors is preferably employed for an electric rotary machine because this stator coil can reduce the size of the coil end (refer to the Japanese patent No. 3118837 or the Japanese patent application laid-open No. 2002-58189).
For example, the Japanese patent No. 3118837 discloses a U-shaped segment (i.e. a rectangular conductor wire covered with insulating film, which is referred to as a segment conductor in the following description) having a pair of leg portions individually inserted into a pair of slots of a rotor mutually spaced at substantially one magnetic pole pitch, with both end portions protruding out of the rotor and being bent substantially in the circumferential direction. The front ends of the leg portions of respective segments are sequentially connected to arrange a stator coil consisting of sequentially connected segment conductors. Accordingly, the head portions of respective segment conductors cooperatively form a head coil end of the stator coil. The end portions of respective segment conductors protruding from the slots cooperatively form a tail coil end of the stator coil.
However, this kind of segment sequentially connected electric rotary machine requires a special or dedicated facility for forming the stator coil. Usually, the stator coil is differentiated according to the type of automotive vehicle and the purpose of its use. Thus, preparing a special or dedicated facility for each vehicle type is disadvantageous and not practical. To solve this problem, the Japanese patent application laid-open No. 2002-58189 proposes changing the wire connection method of the segment sequentially connected stator coil to change the serial turn number of the stator coil.
However, if the above method is employed for a high voltage, high output automotive driving generator motor, the bus bar arrangement for changing the wire connection will become very complicated and accordingly the work will not be easy.